Human fatigue is a temporary inability to maintain optimal cognitive performance. The onset of human fatigue during any cognitive activity is gradual, and depends upon an individual's cognitive ability, and also upon other factors, such as sleep deprivation and overall health. Human fatigue has also been shown to adversely affect physical performance.
In recent years, experts have been emphasizing importance of objective assessment of human fatigue for preventing deaths caused by accidents and overwork in the automotive and occupational fields. For an example in mining industry, the driver of a truck who is on extended work durations need to be attentive to avoid any kind of accidents during the transportation to avoid any loss of assets, life and production time. Similarly, in case of a stock trader, who is involved in trading the equity of high values very frequently needs to be attentive to take appropriate decisions quickly to reduce big losses. Detection of fatigue is critical in various other fields of work also, such as, mining aviation, etc. Upon assessing such fatigue, it is important to make the assessment in real time in practical situations, and to notify the user to pay attention to his fatigue, instead of the conventional fatigue assessments made in laboratories. However, the conventional assessments methods were not non-invasive, non-restraint, or simple, making the methods difficult to use in practical assessments.
Existing techniques usually measure some physiological parameters related to eye and/or a body part, pressure. Electro Cardiography (ECG), etc. and then try to correlate them to deduce to an overall fatigue of the person. Such measurement techniques cause much inconvenience to the person. Additionally, the existing measurements are more of assessing the physical fatigue and not for calculating the mental fatigue of the person. The physical fatigue was evaluated relatively easily in reference to some external indices such as muscular weakness, whereas mental fatigue was evaluated mostly by carrying out surveys or the like. Therefore, it has always been difficult to exclude arbitrariness from mental fatigue evaluation.
Also, the present techniques do not detect mental fatigue levels using non-invasive methods. Hence, it becomes difficult to continuously monitor a person's stress levels and ability to maintain optimal performance.